Sure, here's a simple game that combines elements of Minecraft and Roblox using JavaScript within a single HTML file:
The above code creates a simple game canvas where the player is represented by a red rectangle. You can control the player's movement using the arrow keys on your smartphone. The game continuously renders smoothly by utilizing the `requestAnimationFrame` function. Feel free to customize and modify the code to add more features and elements from Minecraft and Roblox.